Fix minor hashing bug in config_feature_flag configuration name.

Previously, it was possible to have

//package:foo : barbaz

and

//package:foobar : baz

hash to the same value, making it very easy for users to cause a hash
collision by accident. This adds a zero byte after each string so that the
hash will differentiate the two.

RELNOTES: None.
PiperOrigin-RevId: 156216723

1 files changed, 14 insertions, 0 deletions

diff --git a/src/test/java/com/google/devtools/build/lib/rules/config/ConfigFeatureFlagConfigurationTest.java b/src/test/java/com/google/devtools/build/lib/rules/config/ConfigFeatureFlagConfigurationTest.java
index a0de77dfdf..5034db2d25 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/config/ConfigFeatureFlagConfigurationTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/config/ConfigFeatureFlagConfigurationTest.java
@@ -217,6 +217,20 @@ public final class ConfigFeatureFlagConfigurationTest {
   }
 
   @Test
+  public void getOutputDirectoryName_differentiatesLabelAndValue() throws Exception {
+    Map<Label, String> someFlags =
+        ImmutableMap.of(
+            Label.parseAbsoluteUnchecked("//a:a"), "firestarter",
+            Label.parseAbsoluteUnchecked("//b:b"), "second");
+    Map<Label, String> otherFlags =
+        ImmutableMap.of(
+            Label.parseAbsoluteUnchecked("//a:afire"), "starter",
+            Label.parseAbsoluteUnchecked("//b:b"), "second");
+    assertThat(getConfigurationWithFlags(otherFlags).getOutputDirectoryName())
+        .isNotEqualTo(getConfigurationWithFlags(someFlags).getOutputDirectoryName());
+  }
+
+  @Test
   public void getOutputDirectoryName_returnsDifferentValueForSubsetOfFlagValuePairs()
       throws Exception {
     Map<Label, String> someFlags = ImmutableMap.of(Label.parseAbsoluteUnchecked("//a:a"), "first");